


and we take our chances and go along with it

by avosettas



Category: Undertale (Video Game)
Genre: (a weird intersection between the two.), Crosstale Sans (Undertale), Crosstale Sans/Underlust Sans (Undertale), Dirty Talk, Ecto-Breasts (Undertale), Ecto-Penis (Undertale), Ecto-Vagina (Undertale), Knotting, LV 20 Cross, M/M, Praise Kink, Pre-Relationship, Prostitution, Riding, Underlust Sans (Undertale), Vaginal Sex, [head in hands] don't look at me.
Language: English
Status: Completed
Published: 2021-02-05
Updated: 2021-02-05
Packaged: 2021-03-16 15:46:48
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,235
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/29209827
Author URL: https://archiveofourown.org/users/avosettas/pseuds/avosettas
Summary: “i’m sans. but you’re one of those multiverse types, aren’t you?” At Cross’s nod, he continues, “then you can call me lust, or…” He grins and leans in close, “you could me ‘yours’, for a bit.”
Relationships: Sans/Sans (Undertale)
Comments: 2
Kudos: 132





	and we take our chances and go along with it

**Author's Note:**

  * For [2LeryBarBles7](https://archiveofourown.org/users/2LeryBarBles7/gifts).



> raffle prize #1!
> 
> LV 20 Cross was thought up by withtheworms, who is obviously a genius with a galaxy brain, bc LV 20 Cross is SO GOOD i love him so much
> 
> i have been calling this ship "crust" and my friends hate it :) anyway i think these two have CHEMISTRY and now i'm like "what if soft dom lust with cross..." ok bye. (except i'm still thinking about it.)

Cross probably wouldn’t be the first to admit he’s out of his depth here, but at least the locals are avoiding him. They probably think he’ll dust them.

Maybe if pressed, he’d admit that he’d been lost before walking into Grillby’s, but he definitely wouldn’t admit how uncomfortable he was with all the random… well, the random sex stuff. There’d been a dildo shop right next to the alleyway Nightmare had dropped them in, for stars’ sake. 

Which is kind of the whole reason he refuses to ask for directions. Call him a prude, but… this universe makes him feel all kind of heated, from his face to… other parts. If it weren’t for the unconscious warning his LV gives off, it’d probably be mistakable for the LT that afflicts the residents of this universe. 

He’s too busy hunching over his milkshake, pointedly ignoring the stage behind him, to notice the person who sidles up onto the stool next to him. It’s chocolate flavored, and very good, considering that this version of Grillby’s seems to function primarily as a strip club. 

He only notices them when he turns quickly, to prevent the magic that tends to coagulate beneath his right eye socket from dripping directly into his shake. The other skeleton is staring at him, want clear on his face. 

“hiya, big guy,” he purrs. Slowly, he leans up and uses a thumb to swipe the excess magic from Cross’s face. Cross can only stare, though he does vaguely remember Killer mentioning that the Sans of this universe worked at a strip club. 

“H-hi,” Cross stammers, trying to untense. The other seems unfazed by, well, all of him - his horns, his teeth, his size… 

With a soft laugh, he says, “i’m sans. but you’re one of those multiverse types, aren’t you?” At Cross’s nod, he continues, “then you can call me lust, or…” He grins and leans in close; there’s heat radiating from him, an almost feverish warmth. “you could me ‘yours’, for a bit.” 

“I, um,” Cross can feel his face heating up. “I don’t have any money,” he says truthfully. Lust, if anything, smiles a little wider. That’s reassuring, at least; though he could hold his own, Cross really isn’t looking to get into a fight for misspeaking like an idiot. 

“that’s alright, sweetheart. what’s your name?”

“Cross.” 

Lust must teleport them, because the next second, they’re in an unfamiliar bedroom, sitting on the edge of the bed. Lust is still hanging off his shoulder, and Cross can hear the same music that was playing in Grillby’s, coming from somewhere far off. Perhaps they’re still in the same building? 

“well, cross,” Lust purrs, snapping him from his thoughts. “my LT is acting up, and you look like you need a little… stress relief.” 

Cross can practically feel his magic stirring at that. There was a whole club to choose from, and Lust went for him. But, “I’m… probably not as good as you’re used to,” he says earnestly, waiting for Lust to tell him to scram. 

But Lust just laughs, and replies, “sweetie, if you can fuck me, i’ll be plenty satisfied.” He rolls himself onto the bed, flopping against the pillows at the head of it. “my safeword is ‘saccharide’. anything i should know?” His eyes flick up to a point above Cross’s head, before he continues, “and how do you feel about me touching those horns?” 

“You can touch them,” Cross says, twisting to face Lust. He wriggles a bit, maybe trying to entice him, but Cross should probably answer him, even if he already looks wrecked by his LT. “And, uh, I don’t think so.” 

“let me know if anything comes up.” Lust pulls him downwards, and Cross goes with him easily. “anything aside from _this_ , of course.” 

The hand palming him is an unexpected but welcome development - partially because Cross hadn’t realized his magic had manifested already - and Cross groans as Lust squeezes him gently. His hand is so warm. “feels big,” he comments. “i can’t wait to have it inside me.” 

Cross kisses him messily to shut him up, and Lust pulls him closer, one hand grasping one of his horns. His fingers skirt Lust’s ribs as the other moans into the kiss, and Cross licks into his mouth, running his tongue over the flat teeth he finds there. For his part, Lust doesn’t seem put off by Cross’s fangs, haphazardly returning the favor as he smiles best he can through the kiss. 

“feels like a knot,” Lust says with a smirk when they pull apart. He squeezes Cross’s dick again, before leaning back and shucking off his vest and crop top. “i sure hope you’ll be _tying_ me up with it.” 

Cross doesn’t have a reply to the quips, though it’s nice to know that Lust doesn’t find him stupidly intimidating. He surges forward, pressing Lust against the pillows. Then, he sinks his teeth into his collarbone. The resulting keen is practically musical, and beneath Cross’s hands, Lust’s ecto-body takes form. 

His magic is a darker shade of purple, violet to Cross’s lilac, and it seems to get warmer in the room; his whole body feels like it exudes a feverish heat. When Cross trails a hand down his stomach, he can feel how muscular Lust is beneath his soft exterior, and he remembers once again that Lust _works_ here. (He… kind of wants to see how Lust does on one of the poles downstairs, when they’re done.) 

Lust is sensitive - he shivers when Cross strokes his sides, and he moans when Cross touches his breasts. Cross does it again, cupping them in his hand, and Lust is _tiny_ compared to him, so Cross’s hands covers his whole chest. Lust scrabbles at his back as Cross kneads, panting slightly. 

“stop teasing,” he whines. Cross leans down to nuzzle his face, listens to Lust pant right into his acoustic meatus. He’s desperate, and Cross shouldn’t tease, but he can’t help himself. 

“You look nice like this, though,” he mumbles, though Lust probably doesn’t hear it. He’s moaning again, louder now, as Cross pinches his nipples, slowly twisting them. Lust arches towards him, and Cross can’t help the devious smile on his face as he leans down and takes one into his mouth, letting go of its partner to grope at Lust’s breast once more. 

“cross,” Lust whimpers, holding Cross’s skull against his chest. Cross is, maybe, just a little mean, nipping and barely watching his fangs, but Lust gasps and moans each time he feels Cross’s teeth, and that’s an _awfully_ good incentive. 

But Cross isn’t _that_ mean, so eventually he lets up, leaning back once more. Lust is a panting, sweaty mess beneath him, and some of the excess magic from Cross’s eye has been left on his face and chest, too. It’s a very pleasant sight, in Cross’s opinion. “Sounds nice when you say my name like that.” 

Lust whines wordlessly, attempting to kick off his pants while not letting go of Cross - a feat that seems impossible. Cross purrs a bit, the rumbled noise erupting from him unbidden, and works Lust’s stupidly-tight pants off himself. 

He’s practically dripping, and when he sees Cross looking, he spreads his legs almost obscenely wide, holding them up and open by hooking his hands under his knees. “like what you see?” 

Cross nods, and though he knows Lust likely doesn’t need (or want, at this point) the prep, he runs a finger along his slit anyway, dipping into his entrance up to his first knuckle. At the same time, he rubs at Lust’s clit with his thumb, barely getting any traction from how wet he is. 

“Pretty,” Cross mumbles as Lust bucks into his hand. When he pulls it away, it’s soaked. 

“hurry up,” Lust says, rather petulantly. His toes curl as he speaks, and his gaze is trained on the bulge in Cross’s pants. “i feel like i might dust if you don’t fuck me soon.” 

Now, Cross would be the first to admit that he doesn’t know how LT works, but dusting from a lack of sex sounds like… something that could happen, at least in this universe. “I don’t want to hurt you,” he replies, and while it’s probably not what Lust wants to hear, he smiles anyway. 

“sweetie, if i thought you were going to hurt me, i wouldn’t have asked you for this. it’s cute that you’re worried, but trust me, i can take it.” As an afterthought, he adds, “and i’ve got my safeword, too, if i need it.” 

Cross nods, “Please tell me if it hurts. I’d really hate to hurt you.” 

“you’re so sweet,” Lust laughs, “now fuck me, cross. i’d beg, but i think we’re past that point, hm?” 

And damn the bastard, he’s right. Cross shoves his pants down just far enough to release his cock. He still doesn’t feel great about just plowing straight into Lust, though. “I know you don’t… need it, but, um. Do you have any lube?” 

“top drawer,” Lust says, a little sing-song as he gestures towards the nightstand with his head. “you really are sweet, cross. when this passes, i’ll let you take care of me like you want to.” He smiles slyly, as best he can in his position.

The offer makes Cross duck his head shyly as he searches through the drawer. The lube is on top, thankfully, though there’s quite an assortment of… other things beneath it. 

He uncaps it quickly, and Lust watches with lidded eyes as Cross slathers a generous amount over himself. It’s cold, but Lust is waiting on him, and, Cross reasons, he’ll be warm soon enough, considering how warm Lust is. 

“i was right,” Lust murmurs, eyes still on Cross’s cock. “you’re so big, it’s going to feel so good inside me...” 

“I hope so,” Cross mumbles, positioning himself between Lust’s legs. “Can I…” 

“i was ready last week, sweetheart,” Lust replies, a little breathless. So Cross presses in, watching his partner’s face. Lust makes a sound between a sigh and a moan when he bottoms out, pleased as punch. Cross bites back his own moan; he’d thought Lust was radiating heat before, but it’s just on the pleasing side of unbearable now, with his cock is buried in Lust’s cunt. 

“oh, that’s _good_ ,” Lust groans, arching his back a bit. “you feel even bigger than you look, it’s _wonderful_ , sweetheart…” 

He pulls Cross down again by his horns, rocking his hips for friction. Cross takes that as his cue and pulls back a bit, before pushing right back in. Lust seems frustrated with the rhythm, but he doesn’t complain verbally, only moving his hips in tandem with Cross’s and letting out breathy pants. 

“fuck, fuck,” he gasps. “cross, ah, can i ride you?” 

“Please,” Cross blurts before he realizes he’s even consciously processed the question. The next thing he knows, Lust has flipped him onto the sweat-covered sheets, straddling him, now.  
“this is better,” Lust purrs, leaning back a bit. “stars, you’re perfect.” 

Cross would argue that _Lust_ is the perfect one, perched the way he is on Cross’s pelvis, with smears of excess magic on his breasts and face. Before he can open his mouth, though, Lust is pressing his shoulders into the bed for leverage and pistoning himself upwards. 

Lust slams back down, and sets his rhythm to that, much rougher and harder than Cross’s was. Cross isn’t complaining, though - on the contrary, he’s enjoying the ride, scrunching his hands into the sheets to push up into Lust as best he can, meeting the other’s thrusts. 

“so, so good,” Lust pants, pulling one hand from Cross’s shoulders to rub at his clit. “stars, fuck -” His praise-laden dirty talk devolves into babbling, and on one particularly hard thrust, Cross’s knot slips into him, producing a moan that Cross could only describe as _filthy_.

“You look, ah, real good on top of me,” Cross pants, still messily meeting Lust’s thrusts. “You’re, hng, tight, so warm.” 

Lust keens, his free hand scrabbling across Cross’s torso, and he clenches, his bouncing slowing as he cums. Cross picks up the slack, nearing his own orgasm. Lust’s hips feel small under his hands, and he thrusts upwards a few more times, limited by his own knot. 

He tips over the precipice suddenly, managing a couple more good thrusts as Lust shakes above him, still pawing at himself as Cross cums inside him. When Cross slows to simple twitches, Lust slumps onto his chest with a smile, a quiet purr thrumming in his chest. Cross relaxes beneath him, still slightly sensitive. 

“i was right,” Lust says, triumphant but exhausted. “that was very nice.” A hand rubs the base of one of Cross’s horns, much cooler now, but still feverish. “we’ll have to do it again sometime.” 

Cross only nods, winded. 

(He doesn’t remember falling asleep, but when he wakes, there’s a note on his chest, listing a phone number and a work schedule for this week.

 _call me when i’m not working!_ is written on the bottom, with a few hearts drawn beside it.

Cross stares at it for a moment, before checking the time on the digital clock atop the nightstand. 

Resigned, he pulls out his phone. It’s going to be _so embarrassing_ when he has to explain to Nightmare why he missed the agreed upon rendezvous time.)

**Author's Note:**

> and they will do it again sometime. right after cross gets heckled by killer and dust. 
> 
> twitter @avosettas


End file.
